A complex fluid machine, in which a compressor device and an expansion device are integrally formed, is known in the art, for example as shown in Japanese Patent Publication No. H8-86289 (in which a rotating machine of a rolling type piston is shown). A compressor device thereof is used for compressing refrigerant in a refrigerating cycle, whereas an expansion device is operated by working fluid in Rankine cycle.
The compressor device is connected in series with the expansion device, wherein axes of both devices are connected with each other directly or indirectly by a connecting means, such as a magnet coupling. A driving motor and a circulating pump are connected on a side of the expansion device or the compressor device.
The expansion device of the above complex fluid machine is operated by the driving motor for a predetermined time period at an initial stage of the expansion operation (that is a time period during which an operation of the expansion device becomes stable), and then operated by the expansion of the working fluid (high temperature and high pressure gas) in Rankine cycle, so that a driving force (mechanical energy) is generated at its output shaft. The driving force is transmitted to the compressor device through the magnet coupling (or directly) to operate the compressor device. The compressor device compresses the refrigerant in the refrigerating cycle. The circulating pump is operated by the driving force generated at the expansion device to circulate the working fluid in Rankine cycle.
In the above prior art complex fluid machine, a conventional compressor device and a conventional expansion device are simply connected in series. Therefore, such fluid machine needs a space in its longitudinal direction, and has a disadvantage in that it is rather difficult to mount the fluid machine at a desired place of a system, which comprises Rakine cycle and a refrigerating cycle.
Furthermore, since the compressor device and the expansion device are connected with each other by a shaft, each of the devices can not operate independently from the other device. For example, when waste heat for a temperature control of components (e.g. an automotive engine) will be used as a heating source for working fluid in Rankine cycle, in order to effectively use the energy, it is desirable to operate only the expansion device, whereas the compressor device is not operated. However, such an independent operation of the expansion device is not possible in the conventional fluid machine, because the expansion device and the compressor device are connected with each other by the shaft, as described above. As a result, an effective collection of the waste heat from the engine can not be achieved.